Evaluation of Indoor Air Quality in Office Buildings Based on Measurements and User Perception: The Case of the Konya Selçuklu Municipality Service Building

This article aims to evaluate the effects of natural and mechanical ventilation systems on indoor air quality in office buildings, based on experimental measurements and user satisfaction data. The research was conducted at the Konya Selçuklu Municipality Service Building, which has a high user capacity, and four offices with different usage characteristics were selected as a sample. As part of the study, temperature, relative humidity, carbon dioxide (CO₂) and PM₂.₅ concentrations were measured during the summer and winter periods, and indoor environmental data were This article aims to evaluate the effects of natural and mechanical ventilation systems on indoor air quality in office buildings, based on experimental measurements and user satisfaction data. The research was conducted at the Konya Selçuklu Municipality Service Building, which has a high user capacity, and four offices with different usage characteristics were selected as a sample. As part of the study, temperature, relative humidity, carbon dioxide (CO₂) and PM₂.₅ concentrations were measured during the summer and winter periods, and indoor environmental data were compared with outdoor air quality. Furthermore, a satisfaction survey involving 33 employees was used to examine the relationship between physical environmental conditions and user health and comfort. The findings indicate that, during the winter period, temperatures exceeded the recommended comfort limits, whilst relative humidity fell below 30 per cent, creating dry indoor conditions. Depending on user density, CO₂ levels in some offices exceeded the 1000 ppm limit, with the highest value measured at 1835 ppm. It was determined that PM₂.₅ pollution from the outdoor environment was reflected indoors during the winter months, whilst particle levels decreased during the summer period thanks to mechanical filtration. In offices with natural ventilation, opening windows has been found to cause a rapid drop in CO₂ concentrations and effective removal of pollutants. Statistical analyses revealed a moderate positive correlation between temperature and CO₂, and it was observed that an increase in occupant density causes an increase in both parameters. According to the survey results, 66.8 per cent of employees stated that they were dissatisfied with the quality of the indoor air, with the most common health complaints being fatigue, headaches and nasal congestion. The fact that 72.7 per cent of participants reported that their symptoms subsided after leaving the building suggests an increased risk of Sick Building Syndrome. Consequently, it is recommended that natural ventilation be promoted and demand-controlled ventilation systems with CO₂ sensors be implemented in public buildings, alongside the development of user-centred operational strategies, to improve indoor air quality.